US3034878A - High octane motor fuels - Google Patents

Description

May 15, 1962 P. P. MCCALL 3,034,878

HIGH OCTANE MOTOR FUELS Filed Dec. 26, 1957 NUMBERS ON CONTOURS INDICATE I DEVIATION IN CRC RESEARCH OCTANE NUMBER FROM EXPECTED VALUE g E w v o\0 B A M 75 I00 I00 75, 5o

YOL.% CAT. c s

NUMBERS ON CONTOURS INDICATE v |oo(|os.7 RON) CRC RESEARCH OCTANE NUMBERS BLEND A 83% ALKYLATE l7/, CAT. REFORMATE BLEND B 58% ALKYLATE 42 CAT. NAPHTHA A 43L BLEND c v \B 254v ALKYL ATE Q ee/.cAT.c s

100003.? RON) IOO(IO3.6 RON) 75 so 25 VOL.% BINARY BLEND c F IG 2 Patrick P. McCall Inventor y WM, 77 Arforney interactions take place.

' pected due to negative interactions.

United States Patent i 3,034,873 HEGH OTANE MQTUR FUELS Patrick I. McCall, New Monmouth, N..l., assignor to Esso Research and Engineering Company, a corporation of Delaware Filed Dec. 26, 1957, Ser. No. 705,273 7 Claims. (Cl. 44-69) The present invention relates to fuels for use in sparkignition internal combustion engines and more particularly relates to improved gasolines of surprisingly high octane quality produced by the blending of selected petroleum refinery process streams in critical proportions.

' Improvements in engine design, particularly increased compression ratios, have made modern gasoline engines Very sensitive to fuel octane quality. Many late model automobiles now require gasolines of 100 research octane number and it is anticipated that automobile engine octane requirements may rise to even higher levels in the future. In order to keep pace with the increased demand for high octane fuels, gasoline octane levels in general have been raised appreciably in recent years and new super grade fuels have been introduced. There has been little or no corresponding increase in the octane levels of the blending stocks available for manufacturing gasolines. As a result, fuel octane levels are in many cases now approaching the octane levels of the best available blending stocks and it is becoming increasingly more difficult for the petroleum industry to provide gasolines of the requisite octane quality.

The present invention provides a new class of gasolines of surprisingly high octane quality which can be readily blended from presently availablepetr'oleum refinery process streams. The invention is based upon the discovery that certain high octane process streams interact when they are blended together and that the resulting blends have octane values which are either higher or lower than would normally be expected, depending upon whether the interaction is a positive or a negative one. It has been found that when high octane alkylate, catalytic reformate, catalytic naphtha and catalytic C petroleum fractions are blended in critical proportions, positive Blends making use of these positive interactions have octane numbers much higher than those predicted by octane blending correlations and in some cases considerably higher than those of any of the individual streams. in other proportions, blends of the same constituents have the octane numbers predicted by the blending correlations. In still other proportionsithe octane values are considerably lower than would be ex- Since the upgrading of gasoline one octane number at present octane levels may increase the cost of the fuel to the consumer by as much as one cent per gallon, the advantages of gasoline blending to effect positive interactions are obvious.

The exact nature of the invention can be best understood by first considering the methods generally used to predict octane levels in blending gasolines. Research octane numbers are usually computed by first converting the octane numbers of the individual blending stocks to research blending numbers which have been developed empirically from data obtained by actual comparative engine tests of an extremely large number of blends of various constituents. Those blending numbers are then averaged volumetrically to obtain the research blending number of the blend for which the determination is being made. This calculated blending number is then converted to the research octane number. The method for determining motor octane numbers is similar except that empirically determined motor blending numbers rather than research blending numbers are used.

Although both of these methods give accurate results when applied to conventional gasolines and are quite dependable, they do not take into account the interactions which have been found to occur when high octane alkylate, catalytic reformate, catalytic naphtha and catalytic C fractions are blended in accordance with the invention. Catalytic reformate normally has a somewhat higher octane number and a higher blending number than alkylate and therefore it has generally been thought that high octane gasolines should contain catalytic reformate as the major constituent and that alkylate and other high octane blending stocks should be used in much lesser quantities. High octane aviation gasolines blended in the past have, for example, generally contained 50% or more catalytic reformate, about 30% alkylate and up to about 20% catalytic naphtha and other constituents. Since conventional octane blending correlations accurately predict the octane numbers of such gasolines, there was no reason to suspect that higher octane numbers could be obtained by employing alkylate in relatively large amounts and using lesser quantities of the catalytic reformate and other constituents.

in accordance with the present invention, however, it has now been discovered that due to positive or synergistic interactions which occur when alkylate, catalytic reformate, catalytic naphtha and catalytic C hydrocarbons are blended together, surprisingly high octane, gasolines can be produced by using relatively small amounts of catalytic. reformate and larger amounts of alkylate, catalytic naphtha and catalytic C hydrocarbons. Blends containing from about 40 to about alkylate, about 0 to about 35% catalytic reformate and from about 5 to about 60% catalytic naphtha and C hydrocarbons have octane ratings which are as much as 3 octane numbers above those which they would have in the absence of interactions and are therefore highly valuable for use as high octane gasolines. Blends containing from about 50 to about 90% alkylate, about 0 to 20% catalytic reformate and about 1010 about 50% catalytic naphtha and C hydrocarbons have particularly high octane ratings and are therefore preferred.

The alkylate component employed as a blending stock in preparing the fuels of the invention is .a product consisting essentially of branched chain parafins prepared by reacting isobutane,.isopentane or a similar low molecu lar weight isoparaflin with a C 6 or C olefin such as propylene, butylene, isobu'tylene or the like under alkylation conditions. The reaction is carried out in the presence of concentrated sulfuric acid, hydrofluoric acid, aluminum trichloride, boron trifiuoride or a similar catalyst at a temperature in the range of from about 30 to about F. The alkylate product normally boils in the range between about 100 and about 360 F. Alkylate prepared by reacting isobutane and butylene under conditions to yield a maximum of C isoparafiins, particularly trimethylpentanes, is preferred for purposes of the present invention because of its high octane value. Alkylation processes are widely 'used throughout the petroleum industry for producing high octane blending stocks and need not be described at length for purposes of this invention.

Typical alkylate inspections are as follows:

I II

Gravity, API 70. 2 70. 7 5 DistIfllactinnfiAS'iNi' t nl ia oiling oin F 120 106 Ioint. F 172 153 108 185 i 50% Pointi "F 221 60% Point, "F 217 70% Point, "F 220 80% Point, F 223 90% Point, F, 246 231 95% Point, "F 271 238 Final Boiling Point, 333 291 Recovered, Percent. 98. 0 99. 0 l5 Residue, Percent.-. 1. 1 0.7 Loss, Pereent 0.6 0.3 Aromatics, Percent. 1 1. 4 Olefins, Percent 0 0 saturates, Percent 99 08.6 Research Octane No Clear. 95.1 95. 5 +3 ml. TEL/g 100.05 107.53 Motor Octane No., Clear 93.5 04.1 +3 1111. TEL/gal 106 33 107. 40

The catalytic reformate which is utilized as a blending stock in preparing the fuels of the invention is produced by subjecting a naphtha to elevated conditions of temperature and pressure in the presence of a reforming catalyst such as platinumon-alumina, molybdena, chromia or cobalt-molybdenia. Under these conditions, naphthenes in the naphtha are dehydrogenated and isomerized to benzenes, straight chain paraffins are aromatized and isomerized to benzenes and isoparalfins, and normal parafiins are hydrocracked to form shorter chain compounds. The resulting product boils in the range between about 100 F. and about 400 F. and is a highly aromatic stream having a significantly higher octane number than the feed naphtha. There are numerous catalytic reforming processes, all generally similar and well known in the art. In a typical process the feed naphtha is contacted with a platinum-on-alumina catalyst in the presence of 1000-6000 cu. ft./bbl. feed of H at a temperature in the range of from about 900 to 1000 F. and at a pressure of from about 200 to 300 p.s.i.g. with a space velocity of from about 2 to 4 pounds of feed per hour per pound of catalyst.

Typical catalytic reformate properties are as follows:

I II

Gravity, API 44. 2 35. 5 ASTM Distillation:

' 285 50% Point, F 292 257 60% Point, "F 299 70% Point, F.-- 306 80% Point, 31c 90% Point, F 327 295 95% Point, F. 239 307 Final Boiling Point, "F.. 370 336 Recovery, Percent 98.0 98. 8 Residue, Percent... 0.9 0.8 Loss, Percent 1.1 0. 4 Aromatics, Percent; 58. 8 85.0 Olefins, Percent 0.9 0.9 saturates, Percent 40. 3 14.1 Research Octane No., Clear +3 rnl. TEL/gal... 100. 53 108. 94 Motor Octane No., Ole 85.1 94.1 +3 ml. TEL/gal 91.1 100.0

The catalytic naphtha and C hydrocarbons used as blending stocks in accordance with the invention are obtained by fractionation of the product stream from a catalytic cracking unit to recover products boiling from the C range up to about 300 F. The catalytic pentanes and pentenes may be separately recovered and used as blending stocks or instead may be recovered and used with the heavier material in the form of a C to about 300 F. catalytic naphtha. Catalytic cracking is a Well known method for producing relatively low boiling hydrocarbons from gas oils and other high boiling petroleum fractions by contacting such fractions with a silicaalumina, silica-magnesia, clay or similar catalyst at a temperature in the range of from about 900 to about 1000 F. Numerous cracking processes familiar to those skilled in the art may be employed.

Inspections of catalytic naphtha and C hydrocarbons are typically as follows:

Catalytic Naphtha Catalytic Cs'S I II Gravity, API 07. 8 70. 6 88. 3 ASTM Distillation:

Initial Boiling Point, F 180 07 81 149 111 83 151 115 84 163 133 100 203 199 223 I5 217 243 100 97. 4 9G. 0 0. 5 0. 5 0. 4 2. 1 3. "y 5. 8 16. 2 1. 1 79. 7 42. 7 70. 2 14. 5 41. 1 28. 7 93. 2 98. 7 100. 04 100. 94 78. 8 82. 1 82. 5 83. 8 88. l 80. 8

The gasolines of the invention containing the above constituents in critical proportions may boil between about F. and about 450 F. when tested by ASTM Method D-86 and are 95% or more hydrocarbons. They may have vapor pressures between about 7 and 15 pounds per square inch when determined by ASTM Method D-323. Their vapor pressures may, of course, be varied within this range depending upon the season of the year during which they are to be used. The octane numbers of the fuels of the invention are in excess of when determined in accordance with ASTM Method D-908.

The gasolines of the invention may contain from abou 2.0 to about 4.6 ml. of tetraethyl lead, tetramethyl lead or a similar volatile metal anti-knock compound per galion and from about 1.2 to about 3.0, preferably 1.5 to 2.1 theories of a halohydrocarbon scavenger agent. One theory is the amount of the scavenger agent stoichiometrically equivalent to the antiknock agent in the gasoline. This method of expressing scavenger concentrations is a conventional one and will be familiar to those skilled in the art. Halohydrocarbon scavenger agents suitable for inclusion in the gasolines of the invention include alkyl halides such as chlorobromomethane, tetrabromoacetylene, trichloroethylene, ethylene trichloride and ethylene dibromide; alicyclic halogenated hydrocarbons such as chlorocyclopentane and trichlorocyclopentane; aromatic halohydrocarbons such as chlorobenzene, dibromobenzene, trichlorobenzene, dibromotoluene, and bromoxylone; and mixtures of such compounds. Ethylene dichloride and ethylene dibromide are preferred scavenger agents for use in the fuels of the invention.

In addition to a volatile metal anti-knock compound and a halohydrocarbon scavenger agent as described above, the improved gasolines of the invention may also contain solvent oils'consisting of hydrocarbon mixtures having Saybolt viscosities at 100 F. of not more than about 450 seconds, 50% distillation points not more than about 350 F. at 10 mm. Hg and API gravities between about 18 and 28. They may also contain corrosion inhibitors such as amines, amine phosphates and nitrates, and

Santolene C, which is a phosphorus-containing dimer of linoleic acid. Also included may be gum inhibitors such as N,N-disecondary butyl p-phenylenediamine, 3,4-dimethyl--tertiary butylphenol and 2,6-ditertiary butyl-4- methylphenol; anti-icing agents such as isopropanol, hexylene glycol, carbitol and dimethyl formamide; dyes such as 1,4-diisopropy1amino anthraquinone and p-dimethyl aminoazobenzene; dye stabilizers such as ethylene diamine; and other additive materials commonly employed in gasolines.

The invention may be further illustrated by considering results obtained in a series of experiments in which the octane numbers of various gasoline blends were determined and by referring to the accompanying drawings which illustrate fuel compositions and octane levels.

In a first series of experiments blends of alkylate, catalytic reformate, and catalytic pentanes and pentenes were blended in various proportions. The leaded research octane number of each blend was first calculated using conventional octane blending correlations. Tetraethyl lead was added to each blend in a concentration of 3 ml. per gallon and the actual research octane number of each blend was obtained by direct match octane number determinations using commercial reference fuels, as standards. In each case the octane ratings are expressed as Coordinating Research Council Octane Numbers. This rating method is accepted as standard throughout both the petroleum and automotive industries.

Table I ORG R.O.N.+ Alkylate, Cat. Re- Cat. 05's, 3 ml. TEL Blend Vol. Performate, Vol. Per- A CR O N0. cent Vol. Percent R.O.N.

cent I Actual Computed The data shown in Table I and similar data from other tests were plotted to obtain a composition diagram showing the octane ratings of the various blends. This composition diagram is shown in the attached FIGURE 1. It can be seen from FIGURE 1 that blends containing more than about 35% catalytic reformate do not show positive octane number interactions; while blends containing from about 40% to about 95% alkylate, about 0 to 35% catalytic reformate and about 5 to 60% catalytic naphtha or C hydrocarbons have octane ratings which may be as much as 3 CRC octane numbers above the predicted values. The particular advantage of using blends containing from about 50 to 90% alkylate, about 0 to 20% catalytic reformate and about 10 to 50% catalytic naphtha and C hydrocarbons is also shown by FIG- URE 1. Blends containing from 65 to 80% alkylate 0 to 5% catalytic reformate and from to 40% of a catalytic C to 300 F. naphtha are of especially high octane value.

In order to further demonstrate the invention, reference is made to data obtained in a second series of experiments in which a blend of 83% alkylate and 17% catalytic reformate, a blend of 34% alkylate and 66% catalytic C hydrocarbons, and a blend of 58% alkylate' and 42% catalytic naphtha were prepared. Each of these three binary blends had a CRC research octane number of about 103.7. The three binary blends were then blended to-' gether in various proportions and the octane ratings of the final blends were measured by direct match octane number determinations as in the prevlous experiments. The data obtalned are shown in Table II below.

Table II V 01. Per- Vol. PervVol. Per- Actual Blend cent Blend cent Blend cent Blend CRO RON+ A 1 o 2 I 0 a 3 ml. TEL

100 0 0 103.7 0 100 0 105.5 0 0 100 103.7 87.5 0 12.5 105.3 75.0 0 25.0 105.8 50.0 0 50.0 105.7 25.0 0 75.0 104.8 12.5 0 87.5 104.4. 87.5 12.5 0 104.4 75.0 25.0 0 1 104.4 50.0 50.0 0 1 104.4 25.0 75.0 0 104.2 12.5 37.5 0 103.7 0 12.5 87.5 103. s 0 25.0 75.0 103. 5 0 50. 0 50. 0 103. e 0 75.0 25.0 105.5 0 87.5 12.5 105.5 50. 0 30. 0 10. 0 105. 3 e0. 0 10.0 50. 0 100. 0 20. 0 50. 0 20. 0 104. 7 20. 0 20. 0 00. 0 104. 9

l Blend A contained 83% alkylate and 17% catalytic reformate. 2 Blend B contained 58% alkylatc and 42% catalytic naphtha. 3 Blend 0 contained 34% alkylate and 66% catalytic C5 hydrocarbons.

The data of Table II were used to prepare the attached FIGURE 2 which shows the octane values for various compositions of the three binary blends. Even though the three starting blends all had octane ratings of 103.6, cross blends of these had ratings of over 105. This octane number increment clearly illustrates the surprising octane number improvement which can be realized by selective blending to take advantage of positive blending interactions. 7

It will be understood that the fuels of the invention are not limited to fuels containing alkylate, catalytic reformate, and catalytic naphtha and C hydrocarbons alone and that other constituents may be included so long as the alkylate, catalytic reformate and catalytic naphtha and C hydrocarbons are employed in-ratios to one another such that positive interactions occur. Polymer gasoline and butane may be added, for example to a blend containing from 40 to alkylate, from 0 to 35% catalytic reformate and from 5 to 60% of catalytic naphtha and catalytic pentenes and pentanes to provide a fuel having the proper volatility characteristics. Although the presence of such other constituents will afiect the overall octane rating of the gasoline, the benefit of the synergistic interaction between the alkylate, catalytic reformate and catalytic naphtha and catalytic pentenes and pentanes is not lost and higher octane ratings can be obtained than would be possible if these four constituents were blended in ratios such that positive interactions did not occur.

What is claimed is: v

{1. A high octane premium gasoline having an octane number in excess of and containing as the hydrocarbon constituents thereof from about 50 to 87.5% by volume of v I (a) blend A containing 83% by volume of an .alkylate boiling between about 100 F. and about 360 F. produced by alkylation of low molecular weight isoparaffin with a C to C olefin and about 17% by volume of a catalytic reformate boiling between about 100 F. and about 400 F. produced by contacting a naphtha with a reforming catalyst in the presence of hydrogen under reforming conditions; and from 12.5 to about 50.0% by volume of (b) blend C containing about 34% by volume of said alkylate and about 66% by volume of catalytic C hydrocarbons derived from the product stream of a catalytic cracking unit, said high octane gasoline '2 8 yielding a CRC research octane number higher than 5. The gasoline composition of claim 2 wherein said that of any individual blend. minor amount is from 2.0 to about 4.6 ml./gallon. 2. The gasoline composition of claim 1 wherein in 6. The gasoline composition of claim 2 wherein said corporated in said gasoline is a minor amount of a volalead antiknock agent is tetramethyl lead. tile lead antiknock agent. 5 7. The gasoline composition of claim 2 wherein said 3. A high octane premium gasoline having an octane lead antiknock agent is tetraethyl lead. number in excess of 100 and containing as the hydrocarbon constituents thereof about 60% by volume of References Cited in the file of this Patent (a) blend A containing 83% by volume of an alkylate UNITED STATES PATENTS boiling between about 100 F. and about 360 F. 2376 077 oberfen et al May 1945 produced by alkylation of low molecular weight iso- 2394716 Read Feb 1946 parafiin with a C to C olefin and about 17% by 2678263 Glam} 1954 volume of a catalytic reformate boiling between 2761770 'g Sept 41956 about 100 F. and about 400 F. produced by con- 2852356 Lichtenfels Sept 1958 tacting a naphtha with a reforming catalyst in the 15 presence of hydrogen under reforming conditions; FOREIGN PATENTS g}; t 2 52 3 2 1 f 578,552- Great Britain July 3, 1946 r en con ainmg a on 0 i y vo ume 0 sm alkylate and about 42% by volume of a C to 300 OTHER REFERENCES F. catalytic naphtha derived from the product stream 20 Aviation Gasoline Manufacture," Van Winkle, Mc-

of a catalytic cracking unit; and from 10 to about Graw-Hill Book Co., Inc., 1944, first ed., page 199.

30% by volume of Improved Motor Fuels Through Selective Blending, (c) blend C containing about 34% by volume of said by Wagner et 211., Paper presented to Div. of Refining,

alkylate and about 66% by volume of catalytic C 22nd Annual Meeting of the American Petroleum Instihydrocarbons derived from the product stream of a 25 tute, Nov. 7, P941.

catalytic cracking unit, said high octane gasoline Octane Ratings of a Number of Pure Hydrocarbons yielding a CRC research octane number higher than and Some of Their Binary Mixtures, by Smittenberg et that of any individual blend. aL, Jour. of Institute of Petroleum, vol. 26, 1940, pp. 4. The gasoline composition of claim 3 wherein in- 294-303.

corporated in said gasoline is a minor amount of a vola- Practical Design for Better Fuels, by McGuire et a1., tile lead antiknock agent. Technical Papers of the Ethyl Corp., 1956, pp. 1-12.

Claims (1)

1. A HIGH OCTANE PREMIUM GASOLINE HAVING AN OCTANE NUMBER IN EXCESS OF 100 AND CONTAINING AS THE HYDROCARBON CONSTITUENTS THEREOF FROM ABOUT 50 TO 87.5% OF VOLUME OF (A) BLEND A CONTAINING 83% BY VOLUME OF AN ALKYLATE BOILING BETWEEN ABOUT 100*F. AND ABOUT 360*F. PRODUCED BY ALKYLATION OF LOW MOLECULAR WEIGHT ISOPARAFFIN WITH A C3 TO C5 OLEFIN AND ABOUT 17% BY VOLUME OF A CATALYTIC REFORMATE BOILING BETWEEN ABOUT 100* F. AND ABOUT 400* F. PRODUCED BY CONTACTING A NAPHTHA WITH A REFORMING CATALYST IN THE PRESENCE OF HYDROGEN UNDER REFORMING CONDITIONS; AND FROM 12.5 TO ABOUT 50.0% OF VOLUME OF (B) BLEND C CONTAINING ABOUT 34% BY VOLUME OF SAID ALKYLATE AND ABOUT 66% BY VOLUME OF CATALYTIC C5 HYDROCARBONS DERIVED FROM THE PRODUCT STREAM OF A CATALYTIC CRACKING UNIT, SAID HIGH OCTANE GASOLINE YIELDING A CRC RESEARCH OCTANE NUMBER HIGHER THAN THAT OF ANY INDIVIDUAL BLEND.

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